Derivatives of dibenzo-cycloheptadiene and a process of preparing same



by the action of DERIVATIVES F DIBENZO-CYCLOHEPTADIENE AND A PROCESS or PREPARING SAME Georges Muller, Nogent-sur-Marne, France, Bruno Vateh laus, Basel, Switzerland, and, Leon Velluz, Paris,

France, assignors to UCLAF, Paris, France, a French This invention relates to derivatives of dibenzocycloheptadiene and to a method of preparing same, 'and more particularly the present invention relates to a meth- 0d of preparing new derivatives of 4,5-6,7-dibenzo A cycloheptadiene, I, resulting from a transformation of thiocolchicine and having an activity similar to that of colchicine.

This application is a continuation-in-part application of our co-pending application Serial No. 669,468, filed on July 2, 1957, and entitled Derivatives of Dibenzo Cycloheptadiene and a Method of Preparing Samef" now Patent No. 2,911,411. t p p v In copending patent application Serial No. 486,036 of February 3, 1955, now Patent No. 2,820,029, 'the applicant describes the preparation of thiocolchine, II,

. lLwThlocolchicl ne a t methyl mercaptan on colchicine 'It was believed in the past that only those derivatives of colchicine which had preserved at tropolonic structure were capable of exerting the activity'of the starting product. 3

-It has now been found that certain derivatives of dibenzo-cycloheptadiene, 'I, and,in particular, the lactam of 12,13,14-trimethoxy-9-methyl thio-3a-amino4,8-d1hydro 4 4,5-6,7 dibenz'o A cycloheptadiene 8a car boxylic acid III. Ois-lactam referred to as cis-lactam hereinafter, and the racemio mixture of said cis lactam with the corresponding isomeric compound, said racemic mixture being referred to as racemic lactam hereinafter, as well as the lactam of United States Patent O ice,

" Patented June "7, 19 60 p 2 i 12,13,14 trimethoxy 9 methyl thio 3a aminoacid,

IV. Aromatic laotam CHIC OHIO --NH V. Desulturized lactam referred toas dcsulfurized lactam hereinafter, have an activity similar to that of colchicine for research work in plant genetics.

a In order to prepare the cis-lactam, identified as HI hereinabove, the process of the present invention provides that an alkaline salt of methyl mercaptan is caused to react, in an anhydrous medium, with thiocolchicine,

referred toby'Formula II hereinabove, at room temperature. This produces a mixture of products from which the lactam of the Formula III is isolated, which is then transformed by the action vof alkalies into the aromatic lactam, hereinabove illustrated by Formula IV In order to prepare the racemic lactam anotherembodiment of the present invention provides that an alkali metal alcoholate is caused to react, in an anhydrous: medium, with thiocolchicine .of Formulav IIat an:eleva-ted temperature. Thereby amixture of products is produced from which theracemic lactam" is isolated, which is then transformed into the 'racemic aromatic lacta-m? by the action of alkalies.

'I'he"desu1furiz'ed lactam, identified by Formula V givenhereinabove, is produced according to the present invention by splitting off the methyl mercapto group by means of Raney-nickel'in an alcoholic solution.

For carrying out the process of preparing the cislactam according to the present invention, it is sufiicient to prepare a solution of sodium or potassium methyl mercaptide in a suitable anhydrous solvent such as methanol, which can be done easily by introducing a stream of methyl mercaptan into anhydrous methanol, wherein the desired quantity of sodium or potassium metal has previously been dissolved; The thiocolchicine, II, is dissolved in the solution prepared in this manner, which is then allowed to stand at room temperature for two or three days. After dilution with water, the compound is taken up with a solvent which is not miscible with water. such as chloroform, dichloro ethane, or ether, and the organic solvent layer is washed with water. After the organic phase has been dried and the solvent has been evaporated, the" cis-lactam," III, is isolated bychrdmatography.

4,5-6,7 dibenzo A cycloheptadiene ,8 carboxylic The corresponding "racemic lactam is obtained by boiling a solution of thiocolchicine in absolute alcohol in the presence of an alkali metal alcoholate, for instance, by boiling thiocolchicine in absolute methanol in the presence of sodium methylate.

. The cis-lactarn, III, or the corresponding racelnic lactam is subjected in a water-alcoholsolution or in an aqueous alcohol-tetrahydrofurane solution to the action of sodium or potassium hydroxide. at room temperature for about 2-3 days, whereby it becomes aromatic and forms compound IV, or, respectively, the corresponding racemic aromatic lactam, which is isolated and purified by neutralizing the solution with a mineral or organic acid and then by extraction with a solvent which is not miscible with water. The solvent is evaporated and the resulting residue produces, by meansof crystallization, the desired pure aromatic lactam, IV, or, respectively, the corresponding racenu'c aromatic lactam. As stated above, desulfuriaation is effected by a treatmentWitlikaney ni'ekel inan alcoholic medium whereby the lactamof 12,13,14 trimethoxy 3-amino 4,5-6,7-dibenzo cycloheptadiene-8-carboxylic acid is obtained. I

The following examples serve to illustrate the present invention without, however, limiting the same thereto. The melting points given herein are instantaneous melting points determined on the Maquenne block.

EXAMPLEI Preparation of the lactam of 12,13,14-trimethoxy-9- methyl thin-3a-amin0-4,8-dihydr0-4,5-6,7-a'ibenz0-A ficycloheptadieneia-carboxyIic acid, III, ("cis-lactam) treater chromatographically over 300 g. of neutral alu-- .rninumoxide.

Elution of. the residue is carried out as follows: The first 300 cc. of chloroform are evaporated to dryness and yield 3.05 g. of'a' product which, when recrystallized in ethyl acetate, produces 1.9 g. of'the methyl ester of colchicic acid. The following-.1250 cc. ofchloroform permit the recovery of2.7 g; of' unchanged starting thiccolchicine. Finally, 1250' cc. of. chloroform with 1% ethanol yield- 4.3 g. of a product which is subjected to freetional crystallization, first'in ethyl acetate and then in ethanol. Thereby, the desired 'cis-lactam-III, melting point about 258. 6.101" higher, a] '-=-4l5: (c=0.5%, chloroform) is obtained: in the form of yellow crystals, which are insoluble in water, ether, petroleum ether, slightly soluble in ethyl: acetate, and soluble in chloroform.

.The infra-red spectrum revealsthe presence of a 1.688 cm.- band ,.which is characteristic of a 'y-Iactam'.

Analysis of the product shows the formula of Calculated: 64.3% C;-6.2% H; 17.1% 0;: 3.8% N;8.6%

S.'Found: 64.6% C; 6.3% H; 17.3% 0; 3.8% N;

EXAMPLEZ Preparation oft/1e racemic Iactam 0f12,13,14-trimeth0xycycloheptadienc-8-carboxylic acid ("racemic Iactam) 9-methyl thi0-3amino-4,8-dihydro -4,5-6,7-dibenzo-A a e 800 mg. of said compound in benezene/chloroform (1:1) are subjected to chromatographic absorption on aluminum oxide. The absorption agent is eluted by means of benzene/chloroform (1:1). After separation of 60 mg. of the methyl ester. of colchicic acid melting at 250 C., crude racemic lactam is collected and re;

crystall iaed} from absolute ethanol to remove the corresponding dextrorotatory' isomeric compound. Thereby,

Y mg. of the, slightly yellow needles which melt at 264-265" are obtained. The compound has a specific rotatory power of [jot] =O (concentration: 0.5% .in chloroform), is insoluble in water, ether, benzene,i dilute aqueous acids and. alkalies, slightly soluble insacetone, and soluble in ethanol, chloroform, dimetliylformar'nide, and tetrahydrofurane. j AlwlySl'S.-C H Q NS; 373.45. Calculated: 64.32% C; 6.21% H; 17.14% 6; 3;75%-N; 8.58% S. Found: 64.5% C; 6.3% H; 1 7.2% 0; 3.9% N; 8.5% S.

This compound has not yet'been described injthef literature. 1

EXAMPLE 3; f

Preparation of the lactam of 12,13,]4-trimethoxy-9 methyl' thio 3a-amino-4,5-6,7-dibenz0- A ,-cycl0heptadiene-' 8-carb0xylic acid, IV (aromatic laclam) 250 mg. of the cis-lactam compound, III, prepared according to Example 1, are dissolved in 45 cc. of ethanol, 5 cc. of 10 N aqueous sodium hydroxide solution are added, and the solution is allowed to stand at room temperature for two days. The resulting solution is neutralized with aqueous hydrochloric acid; extraction is carried out with chloroform, and the chloroform layer is decanted and dried over magnesium sulfate. Filtration and evaporation of the solvent produces the crude aromatic lactam .IV, which is recrystallized from aqueous ethanol.

I The above procedure yields mg. of pure aromatic.

lactam, IV, melting point +252 C.', [a] =-|:-85"" (c=0.5%, chloroform). The product is colorless, insoluble in water and petroleum ether,,soluble in chloroform and ethanol.

h n ra-red spectrum reveals the'presence of a 11.692 7 cm.- band, which is characteristic of a 'y-lactam. Analysis of the product shows the formula of C H O NS=37L4 Calculated: 64.7% C; 5.7% H; 17.2% 0; 3.8% N

8.6% S. Found: 64.6% C; 5.8% H; 16.8% 0; 3.7% N;

EXAMPLE 4 Preparation of the racemic lactam-cf 12,13,14-trimethth io-3-aminc-4,56,7-dibenz0rA -cyclq-.

0xy-9-methyl heptadiene-ki-carboxylic acid (fracemic aromatic lactam) V cal amount) of colorless crystals'of the racemic lactam of 12,13,14-trimet-hoxy-9-methyl thio-3-amino-4,5-6,7-dibenzo-cycloheptadiene-S-carboxylic acidare obtained. The compound melts at 290 C. and has a specific rotatory power of fulfi l-=0 (concentration: 0.5% in chloroform). The new compound crystallizes in the form of fine and transparent needles, it is unsoluble in Water, ether, dilute aqueous acids and alkalies, and is soluble in alcohol, acetone, and chloroform.

Analysis.--C H O NS=371.44. Calculated: 64.66%

C; 5.69% H; 17.23%. O; 3.77% N; 8.63% S. Found:

64.8% c; 5.3% H;,1'7.2 o; 3.6% N; 8.3% s.

5 EXAMPLE 5 Preparation of the racemic lactam of 12,13,14-trimethoxy 3 am'ino-4,5-6,7-dibenzo-A -cyclheptadiene-8- carboxylic acid, V (desulfurized lactam) 130 mg. of the racemic aromatic lactam prepared according to Example 4, are dissolved in 50 cc. of anhydrous ethanol. 0.8 cc. of a suspension of Raney-nickel containing 1% of palladium (manufactured by the firm Degussa) are washed with alcohol and added. After refluxing for hours, the mixture is filtered over a filter aid (hypercel). The filtrate is evaporated to dryness. The residue is recrystallized from methanol. 75 mg. (66% of the theoretical amount) of colorless and transparent fine needles are obtained which melt at 215 C. and have a specific rotatory power of [a] =O (concentration: 0.5% in chloroform). The compound is insoluble in water, dilute aqueous acids and alkalies, slightly soluble in ether, and soluble in alcohol, benzene, and chloroform.

Anmlysis.-C H O N=325.35. Calculated: 70.14% C; 5.89% H; 19.67% 0; 4.31% N. Found: 70.0% C; 5.9% H; 20.1% 0; 4.4% N.

This product has not yet been described in the literature.

The new compounds are used in the biological and industrial field tor the same purpose for which colchicine is used, particularly for the modification of kariokynes-is and the production of polyploids, and are administered either by spreading aqueous solutions or suspensions thereof on cultivated soil, or by treating seeds in undiluted form therewith or with solutions of said compounds in a suitable solvent or with dusting powders containing said compounds deposited on a suitable carn'er. Solutions of said compounds with concentrations between 0.1% and 2% have proved to be of great value in the treatmentof seeds to produce polyploidism without, however, being limited thereto. Cultivated soil may also be sprayed with such solutions.

Of course, many changes and variations in the start ing materials, the reaction components, the reaction conditions, temperature, and duration, the mode of working up the reaction products and of isolating and purifying the same may be made by those skilled in the art in accordance with the principles set forth herein and in the claims annexed thereto.

We claim:

1. The racemic lactam of 12,13,14-trimethoxy-3- amino 4,5 6,7 dibenzo A cycloheptadiene 8- carboxylic acid.

2. In a process of preparing the lactam of 12,13,14-trimethoxy 3 amino 4,5 6,7 dibenzo A cycloheptadiene-8-canboxylic acid of the formula CHaO CHaO J-NH CHs$ l 0 the step which consists in exchanging the 9-n1enhyl t-hio group of the lactam of 12,13,14-trimethoxy-9-methyl thio 3 amino 4,5 6,7 dibenzo A cycloheptadiene-8-carboxylic acid by hydrogen by treating said compound with Raney nickel in the presence of an alcohol.

References Cited in the file of this patent UNITED STATES PATENTS 2,911,411 Muller et al. Nov. 3, 1959 

1. THE RACEMIC LACTAM OF 12,13,14-TRIMETHOXY-3AMINO - 4,5 - 6,7 - DIBENZO - $1,6 - CYCLOHEPTADIENE - 8CARBOXYLIC ACID. 